Downtown Houston's Main Street boasts some of the most expensive office real estate in the country, according to a new report.

The 1.5-mile-long street ranks No. 21 on JLL's national list of streets with the highest office rents. The average rent for an office space on Main Street downtown is $44.24 per square foot, about 45 percent higher than the city average of $30.55 per square foot, according to the commercial real estate firm.

Trophy towers on Main Street include Hines' 609 Main, Transwestern's 1000 Main and BG Group Place.

Two other Texas cities made JLL's annual list, including Austin and Dallas. Austin's Congress Avenue was the 10th most expensive street nationally with rents averaging $58.20 per square foot. Dallas' McKinney Avenue was the 14th most expensive street with rents averaging $51.17 per square foot.

Nationally, the most expensive streets command average asking rents of $48.65 per square foot, a 47 percent premium over the U.S. average. Despite the higher asking rents, these trophy buildings remain popular with vacancy rates of just 13 percent. These addresses are desired by financial, legal and consulting firms, as well as technology companies.

San Francisco's Sand Hill Road, which is home to several Silicon Valley venture capital firms, was the most expensive street nationally with an average rent of $119.58 per square feet. Sand Hill was followed by New York's Fifth Avenue, San Francisco's Mission Street, Boston's Main Street and Fairfield County's Greenwich Avenue.